(a) Field of the Invention
The present invention relates to a method and apparatus for configuring a frame of an unlicensed band, and more particularly, to a technology of flexibly configuring a frame structure of an unlicensed band cell and signaling the configured frame structure.
(b) Description of the Related Art
With the development of information communication technologies, various wireless communication technologies have been developed. The wireless communication technology may be largely classified into a wireless communication technology using a licensed band, a wireless communication technology using an unlicensed band (for example, industrial scientific medical (ISM) band), or the like depending on a use band. A use right of the licensed band is exclusively assigned to one operator, and therefore the wireless communication technology using the licensed band may provide more excellent reliability, communication quality, or the like than the wireless communication technology using the unlicensed band.
As the representative wireless communication technologies using the licensed band, there is long term evolution (LTE), or the like defined in the 3rd generation partnership project (3GPP) standard. Here, a base station (nodeB (NB)) and user equipment (UE) that support the LTE may each transmit and receive a signal through the licensed band.
As the representative wireless communication technologies using the unlicensed band, there is a wireless local area network (WLAN), or the like defined in the IEEE 802.11 standard. Here, an access point (AP) and a station (STA) that support the WLAN may each transmit and receive a signal through the unlicensed band.
Meanwhile, mobile traffic has grown explosively in recent years. Therefore, there is a need to additionally secure the licensed band to process the mobile traffic through the licensed band. However, the licensed band is finite and the licensed band may be secured by a frequency band auction among operators, or the like. Therefore, it may cost the operators a lot of money to secure the additional licensed band. To solve the problem, a method for providing an LTE service through an unlicensed band may be considered.
An unlicensed band cell configured of the unlicensed band has different features from the existing licensed band cell. The unlicensed band cell opportunistically occupies a channel and therefore cannot continuously occupy a channel for a predetermined time or more. Further, unlike the licensed band, the unlicensed band cell does not have a backward compatibility problem, and as a result can configure a subframe having a new structure. Accordingly, the frame structure of the unlicensed band cell may be differently configured from the licensed band.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.